Waterproof paper bag and method of making same

ABSTRACT

A waterproof paper bag made of paper and a method of forming same wherein at least one side the paper has been coated with a waterproof substance. The waterproof paper bag is manufactured from a sheet of paper which has been coated with a waterproof substance so that at least an inside of the paper bag is coated with the waterproof substance, such as a biodegradable resin, or wax. A piece of waterproof paper is then cut from the sheet and is folded and a flat bottom paper bag with the waterproof coating on an inside of the bag.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No. 62/837,681 filed Apr. 23, 2019, which is incorporated by reference in its entirety herein.

FIELD OF THE INVENTION

This invention relates to a waterproof paper bag and method of making same. More particularly, this invention relates to a paper bag that is manufactured from a sheet of paper which has been coated with a substance that provides a waterproof properties or wax paper so that at least an inside of the paper bag is coated with a waterproof substance.

BACKGROUND OF THE INVENTION

Many stores, such as bulk food stores, provide plastic bags for use to fill from bulk food containers. Generally, these plastic bags are single use and are then discarded. Plastic waste is becoming a serious environmental problem. Frequently, after plastic bags are used, they do not make it to a landfill or recycling facility and much of the plastic produced finds its way into our streams, lakes, and oceans.

SUMMARY OF THE INVENTION

The applicant has appreciated that there is a need to provide an alternative storage container to plastic bags for storing edible goods, for example those purchased in bulk food stores. The applicant has invented a waterproof paper bag that can be used for storing edibles and for example used with bulk refilling of products such as nuts, grains, flour, spices, sugar, pasta, candies, coffee beans, and other such foods. The material used in making the waterproof paper bags of the current invention is a paper such as Kraft paper that has been coated with a waterproof substance such as biodegradable resin that provides waterproof properties but which is biodegradable. Preferably, the biodegradable resin comprises a mixture of starches, cellulose, and vegetable oil. Alternatively, the waterproof coating could be wax, such as paraffin wax. Preferably, the waterproof coating is sprayed onto one side of a sheet of paper prior to making the bag. The paper is then cut to a selected dimension and folded to form a bag with the waterproof coating on one side of the paper which is used as the inside of the bag. The bottom of the bag is then folded such that the bottom is flat and the bag sits up on its own when being filled. The waterproof paper bag of the current invention is resistant to moisture permeability but does not present a health hazard when foods are stored in the bag and in contact with the waterproof coating.

Some “biodegradable” products contain polylactic acid (“PLA”), which is a derivative of plastic materials. PLA is biodegradable only under specific circumstances such as recycling and composting plants which alter conditions such as temperature and are available only in a very few places. In contrast, the applicant has discovered that the waterproof coating comprised of biodegradable resin can completely biodegrade in less than a year under natural circumstances.

In particular, the current invention is advantageously directed to a waterproof paper bag that:

1. Can be mass produced and is bio-degradable; 2. Will not become weak and tear when in contact with moisture; 3. Is safe for contact with edible foods; 4. Is substantially cheaper to produce than plastic bags; and 5. Lessens environmental pollution and waste.

In one embodiment, the current invention resides in a waterproof paper bag comprised of paper having: a bottom, a front, a back, a first side, and a second side with an open top; and the paper having a waterproof coating on an inside surface of the bottom, the front, the first side, and the second side of the paper bag.

Preferably, the waterproof coating is comprised of biodegradable resin.

Preferably, the biodegradable resin is comprised of starches, cellulose, and vegetable oil.

More preferably, the waterproof coating is sprayed onto the paper before the paper bag is formed.

Preferably, the waterproof coating is comprised of wax.

Preferably, the waterproof coating is comprised of paraffin wax.

Still more preferably, the waterproof coating is sprayed onto the paper before the paper bag is formed.

In another embodiment, the current invention resides in a method of making a waterproof paper bag comprising the steps of:

-   -   obtaining a sheet of paper with a waterproof substance coated on         one side thereof;     -   cutting the sheet of paper into a desired dimension;     -   folding the desired dimension into a rectangular tube having a         front, a back, a first side, and a second side, such that the         rectangular tube has a top end and a bottom end with an open         space between the top end and the bottom end;     -   fixing a seam along a longitudinal portion of the rectangular         tube;     -   folding the bottom end of the rectangular tube to form a sealed         bottom of the paper bag; and     -   fixing seams on the bottom of the paper bag.

Preferably, the method comprises the further the step of spraying the sheet of paper with a waterproof substance and allowing the waterproof substance to cure before cutting the sheet of paper into a desired dimension.

Further and other features of the invention will be apparent to those skilled in the art from the following detailed description of the embodiments thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference may now be had to the following detailed description taken together with the accompanying drawings in which:

FIG. 1 shows a waterproof paper bag in accordance with one embodiment of the current invention;

FIG. 2 shows a sheet of paper used in manufacturing the waterproof paper bag of FIG. 1;

FIG. 3 shows a cross-section of the paper sheet of FIG. 2 which has been lined with waterproof coating;

FIG. 4 shows a piece of the sheet of paper of FIG. 2 which has been lined with waterproof coating and cut into a rectangular shape for folding and forming into the waterproof paper bag of FIG. 1;

FIG. 5 shows the piece of the sheet of paper of FIG. 4, folded substantially in half with a portion extending as a fold tab;

FIG. 6 shows the folded piece of paper of FIG. 5 with the fold tab folded over and fixed to the back side of the front of the bag;

FIG. 7 shows the folded piece of paper of FIG. 6 with the bottom end folded up and fixed to form a flat bottom; and

FIG. 8 shows the bag from a side view.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a waterproof paper bag 2 in accordance with one embodiment of the current invention. The waterproof paper bag 2 has an open top 4 and a flat bottom 6 such that the bag 2 sits upright which is ideal when the bag 2 is being filled. The waterproof paper bag 2 also has a front 8 and a back 10, a first side 12, and a second side 14.

At least the inside of the waterproof paper bag 2 is lined with a waterproof substance. Preferably, the waterproof substance is a biodegradable resin. Preferably, the biodegradable resin is a mixture comprising starches, cellulose, and vegetable oil. Alternatively, the waterproof substance can be a wax such as paraffin wax. Preferred dimensions of the bag are a height of 9¾ inches, width of 4¼ inches, and a depth of 2½ inches.

FIG. 2 shows a sheet of paper 20 used in manufacturing the waterproof paper bag 2 of FIG. 1. This sheet of paper 20 has a waterproof coating on one side of the paper 20. The waterproof coating is preferably a biodegradable resin as hereinbefore described. This paper 20 can alternatively be wax paper having a wax coating on one or both sides. Preferably this sheet of paper 20 is mass produced from a roll of paper. Preferably the paper 20 is recycled paper. In one embodiment, one side of the sheet of paper 20 is coated with the waterproof substance, which is preferably sprayed onto one side of the sheet of paper 20 a conveyor system.

FIG. 3 shows a cross-section of the sheet of paper 20 in FIG. 2. As shown, there is a thin layer of waterproof substance 22 on a surface of the sheet of paper 20.

FIG. 4 shows a piece of paper 30 of the sheet of paper 20 of FIG. 2 which has been coated on one surface with a thin layer of the waterproof substance 22. The piece of paper 30 has been cut to a selected dimension with a width X, and a height Y, as shown. The dimensions X and Y are selected so that, once the piece of paper 30 is folded, the bag has the desired dimensions.

FIG. 5 shows the piece of paper 30 folded substantially in half to create a top portion 32 and a bottom portion 34. The waterproof substance coating is on the sides of the top portion 32 and the bottom portion 34 which are folded towards one another. The bottom portion 34 is slightly wider than the top portion 32, and has a piece of paper 30 extending as a fold tab 32. The fold tab 32 has a selected width Y and is subsequently folded over onto the bottom portion 34 and fixed to a back surface of the top portion 32 as shown in dashed lines in FIG. 6.

FIG. 7 shows the folded piece of paper 30 to form the waterproof paper bag 2 of FIG. 1. The first side 12 and the second side 14 are folded along a midline so that the bag 2 is flat when not opened up. This is ideal for storage and shipping. Also as shown, the bottom 6 of the bag 2 is formed by folding a first side portion 40 and a second side portion 42 towards a midline of the bag 2. Then, a back portion 44 of the back of the bag 2 having a trapezoidal share is folded towards the front of the bag 2. Finally, a front portion 46 of the front of the bag 2 also having a trapezoidal shape is toward the back of the bag 2 and is fixed to the back portion 44.

FIG. 8 shows the bag 2 opened up in a side view and standing on the flat bottom 6.

Although this disclosure has described and illustrated certain preferred embodiments of the invention, it is also to be understood that the invention is not restricted to these particular embodiments rather, the invention includes all embodiments which are functional, or mechanical equivalents of the specific embodiments and features that have been described and illustrated herein.

It will be understood that, although various features of the invention have been described with respect to one or another of the embodiments of the invention, the various features and embodiments of the invention may be combined or used in conjunction with other features and embodiments of the invention as described and illustrated herein. 

1. A waterproof paper bag comprised of paper having: a bottom, a front, a back, a first side, and a second side with an open top; and the paper having a waterproof coating on an inside surface of the bottom, the front, the first side, and the second side of the paper bag.
 2. The waterproof paper bag of claim 1, wherein the waterproof coating is comprised of biodegradable resin.
 3. The waterproof paper bag of claim 2, wherein the biodegradable resin is comprised of starches, cellulose, and vegetable oil.
 4. The waterproof paper bag of claim 1, wherein the waterproof coating is sprayed onto the paper before the paper bag is formed.
 5. The waterproof paper bag of claim 2, wherein the waterproof coating is sprayed onto the paper before the bag is formed.
 6. The waterproof paper bag of claim 1, wherein the waterproof coating is comprised of wax.
 7. The waterproof paper bag of claim 6, wherein the waterproof coating is comprised of paraffin wax.
 8. The waterproof bag of claim 6, wherein the waterproof coating is sprayed onto the paper before the paper bag is formed.
 9. The waterproof bag of claim 7, wherein the waterproof coating is sprayed onto the paper before the paper bag is formed.
 10. A method of making a waterproof paper bag comprising the steps of: a) obtaining a sheet of paper with a waterproof substance coated on one side thereof; b) cutting the sheet of paper into a desired dimension; c) folding the desired dimension into a rectangular tube having a front, a back, a first side, and a second side, such that the rectangular tube has a top end and a bottom end with an open space between the top end and the bottom end; d) fixing a seam along a longitudinal portion of the rectangular tube; e) folding the bottom end of the rectangular tube to form a sealed bottom of the paper bag; and f) fixing seams on the bottom of the paper bag.
 11. The method of claim 10, further comprising the step of spraying the sheet of paper with a waterproof substance and allowing the waterproof substance to cure before cutting the sheet of paper into a desired dimension. 